linux-kernel - Re: [RFC PATCH] mm/slab: Add size validation in kmalloc_array

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Message-ID: <aNHBUJxAs-vomIF3@casper.infradead.org>
Date: Mon, 22 Sep 2025 22:36:16 +0100
From: Matthew Wilcox <willy@...radead.org>
To: I Viswanath <viswanathiyyappan@...il.com>
Cc: vbabka@...e.cz, akpm@...ux-foundation.org, cl@...two.org,
	rientjes@...gle.com, roman.gushchin@...ux.dev, harry.yoo@...cle.com,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	skhan@...uxfoundation.org, david.hunter.linux@...il.com,
	linux-kernel-mentees@...ts.linux.dev,
	syzbot+94d20db923b9f51be0df@...kaller.appspotmail.com
Subject: Re: [RFC PATCH] mm/slab: Add size validation in kmalloc_array_*
 functions

On Mon, Sep 22, 2025 at 10:33:57PM +0530, I Viswanath wrote:
> This occurs when the size argument fits into a u32 but is too large 
> to allocate, i.e., when it's between KMALLOC_MAX_SIZE + 1 
> and UINT_MAX (both limits included)

Is it really a good idea to support 2^28 vclocks?  Surely there's a
limit that makes sense to the PTP driver.

Beyond that, this should probably be using kvmalloc_array rather than
kcalloc_array().